Transient Left Bundle Branch Block in the Setting of Hyperkalemia.

Hyperkalemia is a potentially life-threatening condition that can lead to sudden cardiac death. We report a case of transient left bundle branch block (LBBB) pattern on an electrocardiogram (EKG) secondary to hyperkalemia in a patient with a history of end-stage renal disease. A 48-year-old female presented to the emergency department (ED) with chief complaints of weakness and shortness of breath after a missed hemodialysis session. A 12-lead EKG in the ED showed the LBBB pattern with left axis deviation, prolonged PR interval, and peaked T-waves in the precordial leads. The initial serum potassium level was 8.5 mEq/L. EKG changes resolved after correcting the serum potassium level.